Agence France-Presse: French President Nicolas Sarkozy met with UN chief Ban Ki-moon for a working lunch Friday, ahead of a concert here this weekend honoring South Africa’s Nelson Mandela at which the French first lady will perform. During the working lunch at the French consulate in New York at 2:30 pm (1830 GMT), Ban and Sarkozy discussed a variety of key international issues, with a specific focus on climate change. Sarkozy called for new action on environmental issues, which were a major part …